I'm sure there is a program, but not included with Dink, and not that can be d/l at this site. It has been argued about. Reasons against being about people stealing other people's work. The whole purpose of using .d in place of .c files was to prevent this I thought!? As for .d files with Dink, I see no purpose of having .d instead of .c other than as an example. You may ask why some dmods have sources you can d/l? This solely depends on the author and whether he/she wants his/her scripts that he/she worked hard on for someone to be able to take the script and tamper with it. For this reason, I don't think that there will be a converting program released anytime soon if at all.

ADD .d also prevents the player from cheating by changing stuff around. That very well could be another good reason for having .d files.